Into the void

If dopamine were a person, it would be a rockstar. Not necessarily a healthy or emotionally available rockstar, but one that is charismatic enough that everybody keeps talking about them anyway.

Few brain chemicals have achieved the level of cultural celebrity afforded to dopamine. The word itself now appears everywhere. Dopamine detoxes. Dopamine dressing. Dopamine menu. Dopamine snacks. Dopamine-fucking-dissociation from the world. The internet generally portrays dopamine as the “pleasure chemical”, implying that your brain squirts dopamine around whenever something enjoyable happens. But neuroscience is rarely that tidy. And dopamine is considerably more interesting than that.

Surprise!

When I first began researching dopamine during my postdoctoral work at the University of Birmingham, I became slightly obsessed with the idea that the brain fundamentally learns through surprise. Not pleasure, as we can learn about aversive experiences incredibly quickly too. More specifically, dopamine neurons appear highly responsive when something important, novel or unexpected occurs - good or bad.

Imagine you walk into your office at work expecting nothing particularly exciting. But then you see that somebody has left a cupcake on your desk for you. Your reward system fires of a surge of dopamine. Not simply because you know cakes taste good, but because the event violates expectation - it’s not your birthday and you haven’t done anything remotely cake-worthy. Woohoo - unexpected reward. The brain loves prediction errors.

Prediction error is the discrepancy between what you expected to happen and what actually happened. If reality exceeds expectation, dopamine activity increases. But if reality is worse than expected, dopamine activity decreases. Say that cupcake has some sort of gross mould in it because it was left there over the weekend, you eat it and then are horribly sick. Now when you see cupcakes you feel a surge of nausea. The dopamine system helps organisms learn about the world. Dopamine essentially teaches the brain “Hey! Pay attention to this! This is important!” And once something matters, the brain starts building memories around it.

The Bell, the Dog and the Food Hopper

As I mentioned earlier, much of what we know about learning comes from Pavlovian conditioning. Ring bell. Present food. Dog salivates. Repeat enough times and eventually:

Ring bell, dog salivates before food arrives. The cue becomes predictive. The brain learns associations.

Importantly, dopamine activity gradually transfers from the reward itself to the predictive cue. This is crucial. The dopamine spike often occurs not when the reward is consumed, but when the brain anticipates it. This helps explain why the anticipation of food can feel so psychologically intense.

Think about smelling popcorn at the cinema, cracking open a can of soda, the crackle of a chip packet opening. These cues become neurologically loaded. Your brain learns “This event predicts something biologically valuable.” Over time, cues themselves can trigger craving, attention and behavioural motivation. This is one reason why highly processed food environments become so powerful. We are not simply responding to food. We are responding to thousands of learned predictive cues that inhabit our environment.

Wanting Versus Liking

One of the most important distinctions in addiction neuroscience is the difference between wanting and liking. These are not the same thing. Liking refers to pleasure. A whole other team of neurotransmitters like endogenous opioids and endocannabinoids are involved in the generation of pleasure. Wanting refers to motivational drive. Dopamine appears to be much more involved in wanting.

This means it is entirely possible to intensely want something without particularly enjoying it once obtained. Which is honestly a perfect description of many eating experiences.

It’s 2.30pm. You spend thirty minutes obsessively thinking about how the store by your office has half price cookies after 3pm. At 4pm you knock off work and set on a mission to acquire said bargain cookies. You eat cookies on the walk to the subway. By cookie three (well, they were half price, it would be rude not to buy multiples), the emotional experience has become strangely administrative. And yet you continue to eat the cookie. Then the shame sets in. There was no need for even one cookie.

Dopamine is less about satisfaction and more about pursuit. This distinction helps explain why humans repeat behaviours that are not always pleasurable. Compulsive phone scrolling. Gambling. Checking email notifications. Repeatedly opening the fridge despite knowing nothing edible and new has materialised inside. The pursuit itself becomes reinforced. Some of my clients who experience food addiction behaviours can feel their attention drawn to the fridge or the kitchen, and describe almost unconscious “fridge drive-bys” when stressed out, bored or just feeling uncomfortable in themselves.

The Slot Machine Brain

One of the most effective ways to stimulate dopamine systems is unpredictability. Brains love intermittent rewards. This is why slot machines are so psychologically compelling. If a reward occurred every single time, the brain would adapt quickly. But uncertainty Uncertainty keeps the dopamine system engaged.

Modern food environments exploit this beautifully. Limited edition flavours. Seasonal products. New menu items. Mystery candies. A can of soda that might have your name on it.  The brain remains attentive because novelty and uncertainty amplify salience.

Social media operates similarly. Every scroll might reveal something rewarding. Humans increasingly live inside overlapping dopamine economies. Food. Phones. Streaming. Notifications. Online shopping. Dating apps. Continuous novelty. Continuous anticipation. Continuous seeking. Our nervous systems rarely rest.

Dopamine and Modern Exhaustion

One thing that fascinates me clinically and scientifically is how often highly stimulating environments coexist with emotional numbness. People frequently report feeling simultaneously overstimulated and underwhelmed by the world. Viktor Frankl termed the phrase “Sunday neurosis” - a kind of depression which afflicts people who become aware of the lack of content in their lives when the rush of the busy week is over and the void within themselves becomes manifest. But it seems that in modern life this Sunday neurosis can leach into all days of the week and the existential distress can set in any day, any time. So we might as well just fill that void by fiddling around with our phones, or eating junk food, or eating junk food while fiddling around with our phones.

In fact, constant access to rewarding stimuli has been shown to gradually blunt responsiveness. The extraordinary becomes ordinary remarkably quickly. This process, which can be described as “reward downregulation” is seen across multiple forms of repeated high-intensity stimulation. The brain adapts so that a state of overstimulation becomes re-calibrated to a state of normalcy. This means increasingly intense stimulation may be required to generate the same subjective impact in a similar way to the tolerance that is built up.

This is not limited to drugs of abuse. It may occur with food, technology, gambling and other reward-related behaviours.

Importantly though, this does not mean dopamine is “bad”. Dopamine is essential for motivation, learning, movement, reinforcement and survival. Without dopamine, humans would struggle to initiate action. When dopamine neurons deteriorate in Parkinson’s disease, the individual struggles to initiate movements.

The problem is not dopamine itself. The problem is environments that continuously hijack attentional and motivational systems beyond what the brain evolved to manage.

The food or the feed?

At some point while writing this chapter, I absent-mindedly picked up my phone approximately seventeen times despite the face I am already looking at a screen and can access the internet and emails as freely as I want. Smart phones provide miniature intermittent rewards. A text message. A like on my Instagram. An email that I somehow haven’t seen yet. A news alert. A tiny pellet of social validation that I continue to exist in the world.

And crucially, we do not know exactly when these rewards will appear. The uncertainty itself maintains engagement. Food delivery apps are particularly interesting because they merge multiple dopamine-triggering systems simultaneously. Visual food cues. Anticipation. Convenience. Novelty. Tracking updates. Reward. By the time the food arrives, your brain has already been marinating in anticipatory dopamine for twenty minutes, and even if you end up with a semi-cold pizza you’ll likely still order it again.

Memory, Emotion and Craving

Dopamine also interacts closely with memory systems. Emotionally significant experiences are remembered more vividly. This is adaptive as you should remember dangerous situations, rewarding food locations, pleasurable experiences, threatening situations and conversely, the places that make you feel safe.

The issue is that modern brains encode enormous numbers of food-related memories. The café where your ex broke up with you that you can’t enter because the coffee tastes of sadness. The pub that does a great Sunday roast. The ice cream store near the beach that has a really great strawberry cheesecake flavour. The salt and vinegar drenched chips shared after school. The “well earned” wine poured generously after stressful workdays. This is how food becomes woven into emotional life, which means cravings are often not purely metabolic. They may also be autobiographical.

The Rat Who Couldn’t Forget Sugar

One of the most surprising findings from my own early research was how resistant sugar-associated memories were to disruption. We could interfere with cocaine-associated learning relatively effectively. Sugar memories? Much harder.

At first this seemed absurd. Surely cocaine represented the more extreme reward? But from an evolutionary perspective, sugar represents survival. Energy to run away from predators and keep warm at night.

The brain is deeply motivated to remember biologically valuable food sources. And because ultra-processed foods deliver concentrated forms of sugar and fat far beyond ancestral exposure, they may produce unusually strong learning signals. This does not mean sugar is literally equivalent to cocaine. Neuroscience communication online often becomes wildly reductive at this point. But it does mean that highly rewarding foods interact powerfully with neural systems involved in motivation, reinforcement and memory. And importantly, these systems evolved long before industrial food environments existed.

You Are Not Weak

I think one of the most damaging aspects of public conversations around eating behaviour is the assumption that people simply lack willpower. As though humans are calmly making rational nutritional calculations while ignoring kale out of spite. But behaviour emerges from biology, learning, emotion, stress, sleep, environment, memory, social conditioning, reward processing and opportunity. The brain is not a detached logical machine, instead it is a living prediction engine shaped by experience.

If you repeatedly crave hyper-palatable foods under stress, your brain is not failing, it is adapting, sometimes maladaptively, but adaptively nonetheless. And understanding that distinction matters. Because shame rarely improves behaviour long term. Understanding, however, sometimes can.